Messages in this thread | | | Subject | Re: [RFC/RFT PATCH 1/2] sched/core: Check and schedule ksoftirq | From | srinivas pandruvada <> | Date | Mon, 09 Jan 2023 18:33:37 -0800 |
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On Tue, 2022-12-20 at 22:18 +0100, Peter Zijlstra wrote: > On Tue, Dec 20, 2022 at 09:51:09PM +0100, Peter Zijlstra wrote: > > On Mon, Dec 19, 2022 at 02:54:55PM -0800, srinivas pandruvada > > wrote: > > > > > But after ksoftirqd_run_end(), which will renable local irq, this > > > may > > > further cause more soft irq pending. Here RCU soft irq entry > > > continues > > > > Right you are.. what about if we spell the idle.c thing like so > > instead? > > > > Then we repeat the softirq thing every time we drop out of the idle > > loop > > for a reschedule. > > Uff, that obviously can't work because we already have preemption > disabled here, this needs a bit more work. I think it's possible to > re-arrange things a bit. Didn't work. Also when __do_softirq returns, softirq can be pending again. I think if local_softirq_pending(), we can break do_idle() loop.
Thanks, Srinivas
> > I'll try and have a look tomorrow, but the kids have their xmas play > at > school so who knows what I'll get done. > > > diff --git a/kernel/sched/idle.c b/kernel/sched/idle.c > > index f26ab2675f7d..6dce49813bcc 100644 > > --- a/kernel/sched/idle.c > > +++ b/kernel/sched/idle.c > > @@ -381,8 +381,13 @@ void play_idle_precise(u64 duration_ns, u64 > > latency_ns) > > hrtimer_start(&it.timer, ns_to_ktime(duration_ns), > > HRTIMER_MODE_REL_PINNED_HARD); > > > > - while (!READ_ONCE(it.done)) > > + while (!READ_ONCE(it.done)) { > > + rt_mutex_lock(&per_cpu(ksoftirq_lock, cpu)); > > + __run_ksoftirqd(smp_processor_id()); > > + rt_mutex_unlock(&per_cpu(ksoftirq_lock, cpu)); > > + > > do_idle(); > > + } > > > > cpuidle_use_deepest_state(0); > > current->flags &= ~PF_IDLE;
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